Effect of aromatic ring, cation, and anion types of ionic liquids on heavy oil recovery

Surfactant/alkali flooding is one of the best chemical flooding methods to enhance oil Recovery Factor (RF). In this research, Ionic Liquid/Alkali (ILA) mixtures were chosen to address the chemical injection technique. The selected Ionic Liquids (ILs), [EMIM][Cl], [THTDPH][Cl], [EMIM][Ac], [BzMIM][Cl], [DMIM][Cl], [BzMIM][TOS], [dMIM][TOS] and [MPyr][TOS], were introduced to investigate their efficiency in improving the extraction of heavy oil (14o API) from an unconsolidated sand pack at room conditions. Second, these ILs were mixed with synthetic formation brine (3.37 wt. % salts)/alkali (Sodium Bicarbonate [NaHCO3]). Then, 1 Pore Volume (PV) of these composites were injected and flushed with 2 PV of formation brine. The study discussed the influence of cation type, anion type, the structure of the ILs, and the effect of combining ILs and alkali on the RF. The results revealed that these ILs are efficient chemicals for enhancing the RF. ILs with shorter alkyl chain and more aromatic rings are noticeably efficient in enhancing the RF. Finding the right composition ([DMIM][Cl] + NaHCO3) of the chemical slug could increase the additional RF up to 31.55 (% OOIP). The recovery factor results supported by the effects of IL types on the viscosity, Surface Tension (SFT), and Zeta Potential (ZP) supported.